module addRoundKey
#(
  parameter DATA_WIDTH = 128      //Data size for inputs and outputs
)(
  //OUTPUTS
  output [DATA_WIDTH - 1:0] out,  //Data Output to Addition Layer
  
  //INPUTS
  input [DATA_WIDTH - 1:0] in,    //Data Input to Addition Layer - normally plaintext or ciphertext
  input [DATA_WIDTH - 1:0] key    //Data Input to Addition Layer - normally round key
);

assign out = in ^ key;
endmodule
